1. Field of the Invention
This invention relates to the polymerization or copolymerization of olefins using a new catalyst. More particularly, it is concerned with a process for preparing polyolefins characterized by polymerizing or copolymerizing .alpha.-olefins in high stereoregularity using a new catalyst with carrier of high performance.
2. Description of the Prior Art
As a high stereoregular polymerization catalyst for .alpha.-olefins there has been known a catalyst consisting of a titanium halide and an organoaluminum compound. In polymerization using such catalyst system, however, a high stereoregular polymer is obtained, but the yield per titanium component is still insufficient and it is necessary to add a step for removing the residual catalyst in the resulting polymer. To solve this technical problem, there have recently been proposed some high-performance catalysts with a magnesium halide as carrier (see, for example, Japanese Patent Laying Open Prints Nos. 16986/73, 16987/73 and 16988/73).
It is desirable, however, that the polymerization activity as well as the stereoregularity be as high as possible and that the properties of the powder of the resulting polymer be good.